fix: default model for captain assistant (#13496)

lib/llm_constants.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module LlmConstants
-  DEFAULT_MODEL = 'gpt-4.1-mini'
+  DEFAULT_MODEL = 'gpt-4.1'
   DEFAULT_EMBEDDING_MODEL = 'text-embedding-3-small'
   PDF_PROCESSING_MODEL = 'gpt-4.1-mini'
 

spec/enterprise/models/concerns/agentable_spec.rb

@@ -144,13 +144,13 @@ RSpec.describe Concerns::Agentable do
     it 'returns default model when config not found' do
       allow(InstallationConfig).to receive(:find_by).and_return(nil)
 
-      expect(dummy_instance.send(:agent_model)).to eq('gpt-4.1-mini')
+      expect(dummy_instance.send(:agent_model)).to eq('gpt-4.1')
     end
 
     it 'returns default model when config value is nil' do
       allow(mock_installation_config).to receive(:value).and_return(nil)
 
-      expect(dummy_instance.send(:agent_model)).to eq('gpt-4.1-mini')
+      expect(dummy_instance.send(:agent_model)).to eq('gpt-4.1')
     end
   end